Machine for grinding formed cutters



W,- 0. BARNES.

MACHINE FOR GRINDING FORMED CUTTERS.

APPLICATION FILED OCT. 25. 1919.

1,373,587.- Patented Ap 5, 19 1- 3 SHEETS-SHEET 1.

A WM. HHIEUHUM "W WE im/5 ATTORN EY W. O. BARNES.

MACHINE FOR GRINDING FORMED CUTTERS.

APPLICATION FILED OCT. 25, 1919.

1,373,587. Patented Apr. 5, 1921.

3 SHEETSSHEET 2. 5y 6 7 a W,m,,,,,,......

64 lNVENTQR AT'IZORNEY W. 0. BARNES.

MACHINE FOR GRINDING FORMED CUTTERS.

APPLICATION FILED OCT. 25, I919. 1,373,587, Patented Apr. 5, 1921.

3 SHEETSSHEET 3.

INVENTOR AfTORNEY NT cries.

WILLIAM O. BARNES, OF LEOMINFSTEE, MASSACHUSETTS.

MACHINE FOB GRINDING FGBIVIED CUTTER/S.

' Application filed Gcto'bcr 25, 1919.

I! 0 all 10710977. it may concern;

Be it known that I, VILLIAM O. BARNES, a citizen of the United States,resldlng at Leominster, county of lVorcest-er, State ofliilassachusetts, have invented an Improvement in Machines for GrindingFormed Cutters, of which the following is a specification. r

This invention relates to grinding machines, more especially, althoughnot exclusivcly, to machines for grinding formed outtors, examples ofwhich machinesare shown and described in Letters Patent Nos. 1,196,- 420and 1,236,898, issued to me August 29, 1916, and Aug. 14:, 1917,respectively.

T 1e invention has for its objects to provide I an improved grindingmachine in which the cutter is held stationary and the grinding wheel ismoved relative thereto underthe control of a templet; to provide amachine capable of grinding cutters on their own arbors, which resultsin great convenience and saving of time, while producing very accurateresults; to provide convenient means for holding the cutters to beground; to provide simple and effective templet supporting and clampingmeans and means for adjusting said templet relative to the cutter; toprovide improved means for grinding oil the back part of the profileface of a cutter tooth when desired; and to provide improved means fordressing or truing the grinding wheel.

The foregoing and other objects of the invention, together with meanswhereby the same may be carried into effect, will best be understoodfrom the following description of one illustrative form thereof shown inthe attached drawings, wherein;

Figure is a plan view of the machine, the grinding devices beingomitted, and the tcmplet being shown in dotted lines;

Fig. 2 is a front elevation thereof, a cutter (shown in dotted lines)being shown in position to be ground;

3 is an end elevation thereof;

F ig. 4; is a sectional view on the line 4-4 of? Fig. 3 looking in thedirection of the arrows;

Fig. 5 is an enlarged sectional view on the line 5-5 of Fig. 1;

Fig. 6 is a plan view of the portable grinding wheel carrier;

Fig. 7 is a sectional view on the line 77 of Fig. 6;

Specification of Letters Patent.

Patented Apr. 5, 1921.

Serial 110. 833,162. r

Fig. 8 is a side elevation of said grinding wheel carrier;

Fig. 9 is a section on the line 99 of Fig. (3; V

Fig. 10 is a section on the line 10-10 of Fig. 8;

Fig. 10 is a section on the line 10 .-'10 of Fig, 9;

i} Fig. 111153 plan view of an improved iorm oi wneel dressing device;

Fig. 12 is a section on the line 12-42 of Fig. 11, the wheel dressingdevice being shown in the act of truing the grinding wheel;

Fig. 13 is a side view of the grinding wheel illustrating the operationof grinding the profile face of the tooth of a cutter; Fig. 1 1 is aView similar to Fig. 13 showmg the parts adjusted to grind oil the backedge of the profile face of a tooth in order to provide clearance.

In said drawings the numeral 15 indicates the machine base, which ispreferably of such a height as to bring the table supported thereby to aheight convenient for the operator. This base carries two upwardlyentending brackets 16 carrying oppositely disposed center bars 17,preferably provided with detachable centers 17 between v which the workis rotatably supported. The center bars are transversely adjustable bymeans of adjusting screws 18 conveniently operated by hand wheels 19 andare clamped in adjusted position by any suitable means, such as barclamps 20. The base supports a plane work table 21, pivotally connectedthereto as by pivot bars 22, and adjustable on said pivots by a liftingscrew 23. Near its rear edge the work table carries a teinplet 2 1, theforward edgeot' which has the configuration oi the profile edge of thecutter to be ground. The forward edge of the templet may be supported onthe surface of the table by bosses 25 formed on said templet, and therear part of said templet rests upon a step 26 and engages and ispositioned by a shoulder 27, said step and shoulder being both formed onthe table 21. The templet is held in this position by a number of clamprods 30 normally forced upwardly by coil springs- 31 and provided withinclined recesses 32 receiving the inclined ends of clamping bars 33,which may be forced rearwardly when desired by clamp. screws 34: in theforward edge of the table.

the horizontal.

Unlike the machines shown in the prior patents above referred to, thegrinding wheel.

of the present machine is movable over the work table, and tothis endthere is provided a portable wheel carrier carrying an electric motor orother source of motive power for rotating the wheel. This carrier alsosupports a. guide pin which coacts with the templet for properly guidingthe grinding wheel along the edge of the cutter tooth. The wheel carriercomprises a base i0 mounted on adjustable feet 4-1 and carries anadjustable slide 42 formed with a hood or guard 38 supporting betweenits opposite sides ashaft 44 upon which the grinding wheel as isrotatably mounted. As shown in Fig. 7, the shaft 44 is provided with asleeve 37 which is clamped between the opposite sides of the hood 88 bymeans of a nut 36 on said shaft. The sleeve 37 carries two inner hearingraces 45 slidably mounted thereon and disposed concentric with outerbearing races 46 carried by the wheel hub 89. Bearing balls 46 aremounted between the races, and a coil spring 4-7 surrounds the sleeve 37and bears against the inner bearing races at and serves to hold themapart. As the movement of the outer races is limited by the hub, thisspring serves to take up any looseness due to improper fitting or wearin the races and insures a free and steady running of the wheel. The hubof thegrinding wheel is formed with a portion d8 which serves a a beltpulley and receives a belt d9 the other end of which cooperates with abelt pulley 50 carried by the shaft of a motor 51 supported on the slide42. Any suitable conductor (not shown) may be used for supplyg energy tothe motor and it will be obvious that the wheel carrier can readily bemoved over the surface of the table for bringing the wheel into properrelation with the article to be ground. In order to facilitate this itmay be desirable to provide said carrier with a suitable handle 58. Thewheel slide 42 is slidably mounted. upon the base 40 by means of adove-tail 53 on the slide which is received in a dove-tailed groove inthe base. The slide may be adjusted forwardly or rearwardly on the baseby means of an adjusting screw 55 journaled in said slide and havingthreaded engagement with a lug formed on a bracket 5% bolted orotherwise secured to the base. The adjusting screw is preferablyprovided with hand knob 56 which may carry a graduated scale cooperatingwit-h a fixed indicator on the slide. After having been properlyadjusted, the parts are clamped in position by a gib screw 57. Thesliding movement of the wheel slide is in a plane inclined slightly topose as in previous machines, the reason therefor being fully explainedin Patent No. 1,236,898, above referred to.

This is for the same pur- The forward end of the base 40 is providedwith a vertical notch 59 (see Fig. 10). Received in this notch is thelower end of rest rod 60, a truing guide pin 62, and a guide pin 63.Between the rest rod and the truing guide pin is normally inserted adistance piece 61 also received in the notch. The parts 60, 62 and 63are held in the notch by clamp plates 64, G5 and 66, respectively, whichplates are held in clamping position by set screws 67, 68 and 69,respectively, said set screws having conical ends which cooperate withopenings in said plates to retract said plates into clamping engagementwith said parts 60, 62 and 63.

In order to obtain the required clearance angle in grinding a cutter, itis necessary to perform the grinding operation at a point below thehorizontal diameter of the grinding wheel, and the rest rod is sodimensioned as to position its upper end at the desired point, in orderto support the cutter tooth being operated on at the required distancebelow the horizontal diameter of the grinding wheel. The peripheral edgeof the grinding wheel is so shaped that the curvature of a horizontalsection through the wheel at the top of the rest will exactly correspondwith the curvature of the guide pin 63 and will lie in exact verticalalinement therewith. It will be obvious therefore that, if the wheelcarrier be moved sidewise across the table with the guide pin in contactwith the'templet, the path of the grinding point will be a reproductionof the forward edge of the templet and will lie above it in exactperpendicular alinement with respect to the templet and work table. Inorder to secure the proper adjustment of the work table for obtainingthe proper relation between the grinding wheel and the cutter tooth, asquare is laid on the table with one edge bearing against. the templet.The table is then tilted by the table lifting screw 23 until the squarejust comes into contact with the profile edge of the cutter tooth.

As the grinding wheel is gradually worn a. vay during the grindingoperation, and as its peripheral contour must correspond exactly withthe guide pin, there is provided a novel wheel dressing and truingdevice shown best in Figs. 11 and 12. The truing device comprises a base7 2 supported on adjustable feet 73 and carrying a vertical column 74;on which is mounted for vertical adjustment a block 75. The column 74 isprovided with a threadedportion 76 to receive a nut 77 located in anotch or recess in the block 7 5, rotation of said nut serving tovertically adjust said block with respect to the base. Theforward foot73 may be extended to form a dowel pin 78 received in an opening in thebottom of the block 75 for holding the same against rotation on thecolumn 7 1. Secured to the bottom of the block 75, as by screws 79, is abearing plate 80 formed with a V-shaped notch 81.

The truing of the wheel is done by a suitable dressing tool, preferablya diamond 82 mounted in a diamond carrier'83 which is received in atransverse opening8 l near the upper end of the block 7 5. The carrier83 is pressed forwardly by a spring 85 and is clamped in adjustedposition by clamp screw 86. An aperture or pocket 87 formed in the blockimmediately below the diamend serves to collect the material removedfrom the grinding wheel.

The truing of the grinding wheel should take place at aproximately itshorizontal diameter, as at this point a slight error in the verticaladjustment of the diamond will not result in any appreciable differencein the diameter of the wheel and Will, therefore, not cause anyappreciable displacement of the operative portion of the wheel withrespect to the templet guide surface. During the wheel truing operationthe bearing block bears against the truing guide pin (32. This isslightly larger in diameter than the guide pin 63 and is eccentricallyand forwardly disposed with relation to it. The axis of the truing guidepin is displaced from the axis of the guide pin a distance equal to thedifference between the radius of the grinding wheel and one-half of thehorizontal cord of the grinding wheel through the grinding point, forthe reason that the truing of the wheel must take place forwardly of thegrinding point by this amount.

Means are provided for properly positioning the dressing tool withrespect to the bearing block 80, said means, as herein shown, comprisinga cylindrical setting rod 90 permanently secured in a bracket 91,preferably permanently secured to the base of the machine, as shown inFig. 3. The setting rod is clamped in place in substantially verticalposition by means of center pins 92 with its axis perpendlcular to a substantially horizontal portion 93 of the bracket. This setting rod is ofthe same diameter'at its base as the'truing guide pin 62, that being thepoint at which said rod is engaged by the walls of notch 81 in thetruing device. The upper end of the settlng rod. with which the diamondmakes contact, is of the same diameter as guide pin '63. in order toaccurately adjust the dressing tool, the complete truing device is seton the horizontal portion 93 of the bracket and is moved forwardly untilthe notch 81 engages the setting rod, the clamp screw 86 having firstbeen released. The spring will hold the diamond carrier 83 against theupper end of the setting red, and the tightening up of the screw 86 Wlllserve to clamp said diamond carrier in proper posltion.

After a cutter has been sharpened a number of times by grinding backtheprofile face of the teeth, the clearance of the teeth will be lost onaccount of the inclination of the back edge of the teeth and theconsequent widening of the profile face as the teeth are ground down. Inorder to provide the necessary clearance in such cases and place thecutters in condition for further service, it will be necessary merely toremove the distance piece 61, whereupon the rest 60 will be slightlylowered. The tooth will, therefore, be supported in a somewhat lowerposition, enabling the grinding wheel to grind away the rear portion ofthe profile face of the tooth, as will be clear from Fig. 4. 7

While a preferred embodiment of the invention has been shown anddescribed herein in more or less detail, it will nevertheless beunderstood that this detailed description is to be considered merely asillustrative and not as limiting, and that changes and modifications inthe construction shown and described may be made by those skilled in theart without departing from the invention as defined by the claimshereunto appended.

Having thus described my invention, I

claim:

1. A machine of the character described comprising a table, means forsupporting the work above said table, a templet in fixed relation tosaid table, a portable grinder, and a guide pin in fixed relation to andmovable with said grinder, said grinder being movable over the surfaceof said table with said guide pin in engagement with said templet, andsaid portable grinderand guide pin being in vertical alinement, wherebysaid work is ground to the shape of the templet.

2. A machine of the character described comprising a table, means forsupporting the work above said table, a templet in fixed relation tosaid table, a portable grinder having a grinding wheel, and a guide pincarried by said grinder in vertical alinement with the operative pointin the periplr cry of said grinding wheel, said grinder being movableover the surface of said table with said guide pin in engagement withsaid templet, whereby said work is ground to the shape of the'templet.

3. A machine of the character described comprising a table, means forsupporting the work above said table in fixed relation thereto, aportable grinder movable over said table, and cooperative guiding meanscarried by said table and grinder for limiting the movement of saidgrinder toward said work, said guiding means being in vertical alinementwith said work supporting means and portable grinder.

a. A machine of the character described comprising atable, means forsupporting the work above said table in fixed relation thereto, aportable grinder movable over said table, and cooperative guiding meanscarried by said table and grinder tor limiting the movement of thegrinder toward said work, said means comprising a templet carried by oneof said parts and a guide pin carried by the other of said parts, andsaid templet being in vertical alinement with said work supporting'means.

5. A machine of the character described comprising a table, means forsupporting the work above said table in fixed relation thereto, aportable grinder movable over said table, and cooperative guiding meanscarried by said table and grinder for limiting the movement of thegrinder toward the work, said means comprising a templet carried by saidtable and a guide pin carried by said grinder, said templet and guidepin, respectively, being in vertical alinement with said work holdingmeans and grinder,

6. A machine of the character described comprising a table, means forsupporting.

the work above said table in fixed relation thereto, a portable grindermovable over said table and having a grinding wheel, and cooperativeguiding means carried by said table and grinder for limiting themovement of said grinder toward the work, said means comprising atemplet carried by said table and a guide pin carried by said grinder,said guide pin being in vertical alineinent with the operative point inthe periphery of said grinding wheel.

7. A machine of the character described comprising a table, means forsupporting the work above said table in fixed relation thereto, aportable grinder movable over said table and having a grinding wheel,and cooperative guiding means carried by said table and grinder forlimiting the movement of said grinder toward the work, said meanscomprising a templet carried by said table and a guide pin carried bysaid grinder, said guide pin being in vertical alinement with theoperative point in the periphery of the grinding wheel and having acurvature corresponding to the curvature of the horizontal section ofthe wheel periphery at the grinding point.

8. A machine of the character described comprising a support providedwith a table, uprights carried by said support, work holding centerscarried by said uprights, a portable grinder moval is over said table,and cooperative guiding means carried by said table and grinder forcontrolling the movements of said grinder.

9. A, machine of the character described comprising a support providedwith a table, uprights carried by said support, work holding centerscarried by said uprights, a portable grinder movable over said table, atemportions thereof.

plet fixed to said table, and a guide pin car- ,ried by said grinder andcooperating with said templet.

10. A machine for grinding the profile faces of formed cutteiiteethcomprising a table,vmeans for supporting a cutter above said table infixed relation thereto, a portable grinder movable over said table, andcooperative guide means carried by said table and grinder for limitingthe movement of said grinder toward said cutter, said means comprising atemplet carried by one of said parts, a guide pin carried by the otherof said parts, and a rest carried by said grinder for supporting theteeth of said cutter.

11. A machine for grinding the profile faces of formed cutter teethcomprising means for supporting a cutter, a grinder, said supportingmeans and grinder being relatively movable to cause said grinder tooperate upon said cutter, and a rest for supporting the teeth of saidcutter in proximity to said grinder, said rest being normally fixed withrespect to said grinder but being adjustable with respect thereto tovary the point of operative engagement of said cutter with said teeth.

12. A machine for grinding the profile faces of formed cutter teethcomprising a table, means for supporting a cutter above said table infixed relation thereto, a portable grinder movable over said table, 00-operative guiding means carried by said table and grinder for limitingthe movement of said grinder toward the cutter, said means comprising atemplet carried by one of said parts and a guide pin carried by theother of said parts, a rest for supporting the teeth of said cutter, adistance pieceunder said rest for positioning it to support the cutterteeth for grinding their profile faces, said piece being removable forpermitting the lowering of the rest to support the teeth in position forgrinding the back 13. A machine of thecharacter described comprising atable having a step and a shoulder, a templet supported on said stepagainst said shoulder and having bosses resting on the surface of saidtable, clamp rods guided for movement in said table and having notchesto receive the edge ofsaid templet, said clamp rods having inclinedrecesses, clamping bars guided for movement in said table and providedwith inclined ends cooperating with the recesses in said rods, and

15. A portable grinder, a base therefor having a vertical notch, a restand a guide pin in said notch, a distance piece between said rest andguide pin, and means for clamping said rest and guide pin in place inthe bottom of said notch, said means comprising clamping plates formedwith apertures to receiver said rest and pin, respectively, and clampingscrews for retracting 10 said plates.

16. A machine of the character described comprising a base, a templet,means for supporting work in fixed relatlon to the templet, a movablegrinding wheel carrier,

a grinding wheel thereon, a guide pin in 15 In testimony whereof I aflixmy signature. 20

WILLIAM O. BARNES.

